Effects of Electric Motor Speed and Direction of a Horizontal Rotary Dyeing Machine on Indigo Dyeing Quality and Performances

Indigo-dyed fabrics have unique color and properties which leads to their high demand for the textile and apparel industry. However, there are several involved processes for producing and preparing from the natural indigo plants which would take around 15–20 days in total while there are 9–11 days required even only for the dyeing process. As a result, many dyeing machines have been developed in order to reduce the dyeing time. This paper presents the effects of the rotating speed and direction of an electric motor on indigo dyeing quality and performances for a horizontal rotary dyeing machine. The dyeing machine prototype was designed to allow adjustable rotating speed and rotation direction when dyeing. Traditional Thai cotton was used as the sample fabrics for this research. The experimental test results showed that the rotating speed around 30 RPM (equivalent to 0.08 m/s at the dyeing point) provides the best dyeing quality. The dyeing time of approximately 30–35 minutes was the optimum time for medium-rather high dyeing quality for one rotating direction while 5–15 minutes was for alternating rotation direction for every 15 seconds. These results can be used to design the dyeing machine to reduce the indigo-dyeing time while retaining high dyeing quality and less-energy consumption for the machine.